Melanoma (also called malignant melanoma) – a form of skin
cancer that arises in melanocytes (the cells that produce pigment) and that may
spread rapidly to other parts of the body if not diagnosed and treated early. A
melanoma may begin as a mole. Melanomas are the most dangerous type of skin
cancer and the main cause of death from skin cancer.

Basal cell carcinoma (BCC): the most common non-melanoma skin
cancer. It begins in the lowest layer of the epidermis, called the basal cell
layer. It usually develops on sun-exposed areas, especially the head and neck.
BCCs are slow-growing and hardly ever spread to other parts of the body.

Squamous cell carcinoma (SCC) – a type of cancer that begins
in squamous cells – the thin, flat cells that look like fish scales and that are
found in the skin and in tissues that line certain organs of the body. Only
occasionally do these cancers spread to other tissues. They are the second most
common form of skin cancer.